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In classical mechanics, a gravitational field is a physical quantity. [5] A gravitational field can be defined using Newton's law of universal gravitation. Determined in this way, the gravitational field g around a single particle of mass M is a vector field consisting at every point of a vector pointing directly towards the particle. The ...
This formulation is dependent on the objects causing the field. The field has units of acceleration; in SI, this is m/s 2. Gravitational fields are also conservative; that is, the work done by gravity from one position to another is path-independent. This has the consequence that there exists a gravitational potential field V(r) such that
It is defined so that the gravitational force experienced by a particle is equal to the mass of the particle multiplied by the gravitational field at that point. Gravitational flux is a surface integral of the gravitational field over a closed surface, analogous to how magnetic flux is a surface integral of the magnetic field. Gauss's law for ...
Gravimetry is the measurement of the strength of a gravitational field. Gravimetry may be used when either the magnitude of a gravitational field or the properties of matter responsible for its creation are of interest. The study of gravity changes belongs to geodynamics.
A common misconception occurs between centre of mass and centre of gravity.They are defined in similar ways but are not exactly the same quantity. Centre of mass is the mathematical description of placing all the mass in the region considered to one position, centre of gravity is a real physical quantity, the point of a body where the gravitational force acts.
The gravitational constant appears in the Einstein field equations of general relativity, [4] [5] + =, where G μν is the Einstein tensor (not the gravitational constant despite the use of G), Λ is the cosmological constant, g μν is the metric tensor, T μν is the stress–energy tensor, and κ is the Einstein gravitational constant, a ...
Additionally, it can be shown that any massless spin-2 field would give rise to a force indistinguishable from gravitation, because a massless spin-2 field would couple to the stress–energy tensor in the same way gravitational interactions do. This result suggests that, if a massless spin-2 particle is discovered, it must be the graviton. [5]
g is the gravitational field strength v is the velocity of the rocket Then the time-rate of change of the specific energy of the rocket is v ⋅ a {\displaystyle \mathbf {v} \cdot \mathbf {a} } : an amount v ⋅ ( a − g ) {\displaystyle \mathbf {v} \cdot (\mathbf {a} -\mathbf {g} )} for the kinetic energy and an amount v ⋅ g {\displaystyle ...